Scott,
   You are right in the fact that you can only go direct in a radar environment.  There are no ways around it.  If you are flying direct using anything other than ground based navigation such as VOR's, and are outside navaid limitations, etc, you must be in radar contact in order to fly direct.  There are areas out here in CO that there is no radar coverage below about FL190, so even if you are way up there (at least way up for a Lancair), you cannot go direct unless you are direct to a VOR and within navaid limitations.  I say there is no way to do this, but there is one way and that is to go OTP.  In that case ATC is not required to separate you from other aircraft and therefor you can go direct even in a non radar environment.   All of these rules are way out of date.  Just another FYI, I'll bet there are a bunch of you out there flying in the IFR environment using GPS that do not have the required documentation from the local FSDO.  You cannot fly legally without this paperwork, and also includes a POH suplement.  I give WINGS seminars on this subject all over the Mountain states, and can elaborate more if there is interest.  

Ron Galbraith
LNCE N5ES

>
> ..............But they concluded in their written summary that the
> required navigational equipment statement in 91.205 says that you can’t
> use GPS for your primary navigation system because it is not
> ground-based.
>

> equipment code of
> LNC2/G indicates advanced RNAV.  Utilizing AIM  5.1.7.d.3(a), it's doable in
> an ATC radar environment - Aha!  The required  ground equipment is ATC radar.